用AFLP技术检测慢生型花生根瘤菌竞争结瘤的研究

A test on competition in nodulation ability of peanut bradyrhizobia by AFLP fingerprinting method

以 5株慢生型花生根瘤菌和天府 3号花生为材料 ,用 AFLP技术研究了慢生型花生根瘤菌 Spr2 - 9、Spr3- 3、Spr3- 5、Spr4- 5和 Spr7- 1的遗传特性和竞争结瘤能力。结果显示 ,供试条件下 ,传代次数对菌株的遗传性状无明显影响 ,2 8℃培养条件下 ,花生根瘤菌连续传 96代 ,其 AFLP指纹未发生明显变化 ;37℃培养 ,仅 Spr3- 3和 Spr3- 5能够存活并正常生长 ,其 AFLP指纹也未发生明显改变 ,然而其它菌株不能生长。将供试慢生型花生根瘤菌分别接种天府 3号花生 ,光照培养 30 d后 ,随机各取 4个根瘤 ,从根瘤中提取类菌体 DNA进行 AFLP分析 ,各根瘤类菌体 DNA的 AFLP指纹图谱与该菌株纯培养物 AFLP指纹相同。将 5个菌株混合接种天府 3号花生 ,不同菌株的占瘤率存在差异 ,Spr3- 3和 Spr3- 5的竞争结瘤能力最强 ,两菌株的占瘤率之和为 85.4% ;Spr4- 5的占瘤率为 1 2 .2 % ;Spr7- 1为 2 .4% ;而 Spr2 - 9的竞争结瘤能力最差。本试验结果说明 ,AFLP技术用于根瘤菌生态和竞争结瘤能力研究 ,具有下列优点 :简易、快速、准确 ;直接取豆科植物的根瘤提取 DNA,进行原位研究 ;在不改变菌株遗传特性 ,即不使用突变株的前提下 。

The hereditary character and the nodulation competition ability, with the Tianfu No.3 peanut cultivar, were determined by AFLP fingerprinting method with Five p eanut bradyrhizobial strains of Spr2 9, Spr3 3, Spr3 5, Spr4 5, and Spr7 1. The results showed that: the variation of AFLP fingerprinting for all of the ex perimental strains cultivated at 28℃ as well as the strains of Spr3 3 and Spr3 5 incubated at 37℃ in YMB medium for 96 generations was not obvious, howeve r, the strains of Spr2 9, Spr4 5, and Spr7 1 could not grow at 37℃; the nodu lation competition rate was 85.4% for the strains Spr3 3 and Spr3 5 together, 12 2% for Spr4 5, 2 4% for Spr7 1, and zero percent for Spr2 9; Spr3 3 and Spr3 5 were thus the best strains due to the highest nodulation competition ra te an d well growth ability at 37℃. In general, the results suggested that AFLP finge rprinting was a good method to differentiate the studied strains, and it is an e asy, rapid and accurate method for the research on ecology and effective strains selection of Rhizobia.